From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sridhar Samudrala Subject: Re: VLAN ID 0 with priority tagging Date: Thu, 06 Feb 2014 21:29:58 -0800 Message-ID: <52F46F56.6070007@gmail.com> References: <52E05901.6050601@us.ibm.com> <52F4207A.6020408@gmail.com> <52F431F6.9010605@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: Toshiaki Makita , "netdev@vger.kernel.org" Return-path: Received: from mail-ob0-f172.google.com ([209.85.214.172]:51755 "EHLO mail-ob0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750712AbaBGF3t (ORCPT ); Fri, 7 Feb 2014 00:29:49 -0500 Received: by mail-ob0-f172.google.com with SMTP id vb8so3474812obc.3 for ; Thu, 06 Feb 2014 21:29:49 -0800 (PST) In-Reply-To: <52F431F6.9010605@lab.ntt.co.jp> Sender: netdev-owner@vger.kernel.org List-ID: On 2/6/2014 5:08 PM, Toshiaki Makita wrote: > (2014/02/07 8:53), Sridhar Samudrala wrote: >> On 1/22/2014 3:49 PM, Sridhar Samudrala wrote: >>> I am trying to send a packet with VLAN ID 0 and non-zero priority. >>> >>> The VLAN interfaces are created on 2 hosts using >>> ip link add link eth1 eth1.0 type vlan id 0 egress-qos-map 0:2 >>> >>> When i try to send a packet using ping/arping, on the sender side tcpdump >>> shows that the VLAN tag is added with ID 0 and priority 2. >>> >>> However, the receiver is receiving the packet with vlan tag stripped. >>> >>> I am seeing the same behavior with multiple NICs and also with a >>> switch in >>> between the 2 hosts or with the 2 hosts connected over loopback cable. >>> >>> It looks as if the driver on the send side is stripping the tag if >>> vlan id is 0. >>> Is this correct behavior or a bug? >>> Any clues on how to get priority tagging to work with vlan id 0? >>> >> I sent this note a few weeks back, but i haven't seen any response so far. >> >> Is priority tagging with VLAN ID 0 not supported or is this a bug? >> It looks like the NIC hardware is stripping the VLAN tag if the id is 0 >> even when VLAN tag >> is added by the software. > eth1.0 should be able to send frames tagged with vid 0. > Though I don't know whether there are NICs/drivers that strip tag 0, I > can send frames with vid 0 (with e1000e). > > Good to know that it works with e1000e. I guess you are seeing the frames with vid 0 at the receiver. I have tried with ixgbe and be2net and both of them seem to strip tag 0. Thanks Sridhar